EP3458327B1 - Method for controlling the drive train of a hybrid motor vehicle and device for carrying out the method, in particular in a trike - Google Patents

Description

The invention relates to a control method for the at least one electric motor and at least one internal combustion engine drive train of a hybrid motor vehicle according to the preamble of claim 1, according to the invention with the help of the electric motor alone up to 150 km completely exhaust-free and beyond with no range restriction to be able to drive a maximum consumption of the internal combustion engine of 1.5 l / 100 km with minimized emissions.

Since September 1, 2014, the Euro 6 standard applies to type testing for new passenger vehicles throughout Europe, which has been binding for all newly registered vehicles since September 1, 2015.

This European emissions standard sets relatively ambitious limits for exhaust gases containing carbon monoxide, nitrogen oxides, hydrocarbons and particles. A vehicle manufacturer must guarantee compliance with these limit values for a specified period of time and mileage.

An internal combustion engine operated with liquid combustion fuels (e.g. diesel engine, gasoline engine) is still the most widespread drive in motor vehicles, in particular because it is possible to achieve a far greater range with a single tank filling than with the charging capacity of an electrical energy store feeding the electric motor ( e.g. accumulator, supercapacitor). In addition, performing refueling is still more time-saving and convenient compared to recharging an electrical energy storage device.

However, a disadvantage is the exhaust gas and fine particle emissions generated during the combustion process, in particular of carbon dioxide, nitrogen oxides, hydrocarbons and other, primarily fine-particle pollutants in the nanometer range, which can lead to environmental pollution and health problems in humans.

The alternative replacement or supplementary use of electric motors is due to the presence of light and high-capacity energy stores, e.g. of lithium batteries and supercapacitors, increasingly common in motor vehicles, especially in combination with internal combustion engines in hybrid motor vehicles. However, the relatively expensive and heavy accumulators of up to several 100 kg remain disadvantageous, the short ranges, which are still very limited compared to motor vehicles powered by internal combustion engines, and the higher recharge frequencies required as a result, and / or the provision of relay stations for the exchange of discharged accumulators. Rechargeable batteries are already available quickly, but this affects their lifespan. In addition, a battery can be recharged a maximum of approx. 2000 times with 80% discharge.

The electric drive is superior to the common drive with internal combustion engines in various properties. These include, for example, its advantageous torque and power characteristics, the mostly simpler structure of the drive train and the almost complete absence of emissions in terms of pollutants and noise. Likewise, fewer vibrations occur than in internal combustion engines that operate conventionally as piston engines. With their significantly higher efficiency and in the absence of no-load losses, electric motors also require significantly less energy.

In the prior art, attempts are made to compensate for the range disadvantage of the electromotive drives with extender solutions (for example, Getrag KG, Bosch GmbH). In this case, either a separate internal combustion engine in the transmission or a direct-current combustion generator is installed in the motor vehicle as a charger for the accumulator. The range extender is not used to increase the drive power of the motor vehicle and is not strong enough to generate the total energy required during driving. By installing such an additional generator in electric vehicles, the range is increased, but it is still limited compared to vehicles operated with internal combustion engines.

The U.S. patent document 2013/0218383 A1 discloses a serial hybrid drive, the drive wheels of which are driven by an electrical drive fed by an electrical energy store and whose internal combustion engine is designed as a range extender which extends the range, the generator-operated power generation of which feeds the electrical energy store. To control the power output of the internal combustion engine as a function of the driving speed, the power requirement actually required in the given driving situation (uphill, downhill, acceleration phase, braking phase) is determined on the basis of a model-specified power requirement and the difference between the model-specified and the actual power requirement is determined and the internal combustion engine is operated in accordance with the resulting power difference. The output of the internal combustion engine operating as a range extender is thus continuously adjusted via the difference between its ideal power requirement and a real power requirement in accordance with the specific driving situation. The actual power requirement is determined on the basis of various sensor signals or status queries, in particular the state of charge and the current supply or the current draw of the electrical energy store, and by means of sensor-controlled status queries of the accelerator pedal or brake pedal.

The EP patent document 0903 258 A2 relates to a hybrid motor vehicle with a specially designed system for the recuperation of kinetic energy into electrical energy, wherein in the event of a deceleration of the motor vehicle triggered by fuel supply termination depending on its speed and depending on the remaining capacity of a storage device for electrical energy and depending on the temperature of a drive control circuit of one Engine control unit regeneration quantities are generated and wherein an internal combustion engine control unit acted upon by this and processing this controls a pump loss control device in such a way that the pump losses of the internal combustion engine become as low as possible.

From the DE 10 2011 002 742 A1 and DE 102 60 435 A1 Methods are known which disclose how an internal combustion engine can be connected to or removed from the electric motor while driving with the aid of an electric clutch without impairing driving comfort. Both the power of the electric motor is briefly increased during the closing of the electric clutch to start the internal combustion engine and, if necessary, the transmission is downshifted. After the internal combustion engine has been started and the required power has been provided or has been completely separated, this process is ended.

From the DE 10038181 B4 A method is known of how, in the case of a hybrid drive with at least one electric drive unit, torque target values acting on the individual drives can be determined and distributed to the drives according to the driver's wishes and vehicle operating parameters. It is also disclosed that braking energy is recoverable and / or the internal combustion engine can be used to charge an accumulator during operation.

From the DE 4324010 C2 A method for controlling the torque output of a hybrid drive is known, whereby a motor vehicle driver is able to switch between electric drive and hybrid drive by means of a simple adjusting device, so that the vehicle can also be operated purely electrically and in a fuel-saving manner.

In the prior art, torque outputs of the internal combustion engine and of the electric motor that contribute to the required total drive torque of a hybrid vehicle are distributed to the individual drives in a highly efficient but also highly complex manner. Since this distribution is also influenced by an intermediate transmission, there are quite complex control procedures which have to differentiate between different operating states and which also interact very specifically with individual vehicle components.

In addition, the previously known methods do not allow individual solutions that have already been certified with regard to compliance with exhaust gas standards to be combined with one another, in order to thereby develop much simpler and less problematic developments of one Motor vehicle to get or to use these individual solutions for other vehicles.

Since exhaust gas emissions are defined in grams per km according to the Euro emissions standards to be observed, this means that each engine variant for a vehicle type (e.g. VW Golf, Passat, Polo etc.) must be checked individually on the respective vehicle. In the event of any changes to vehicles, in particular changes to vehicle parts (e.g. engine, body, etc.), the tests must therefore always be repeated, since different exhaust gas values can occur with a different engine or even with identical engines due to changed body shapes. With the many existing engine variants per vehicle type and the various vehicle types themselves, the number of tests required increases considerably.

Again, the invention tries to remedy this, i.e. reduce the number of emissions tests required for a vehicle type.

It is known that mechanical energies which are contained in a system can in principle be reused or can be recovered in electrical energy. However, the conversion inevitably always involves thermal losses. Recoverable energies in vehicles are the kinetic energies achieved by dynamic accelerations as well as the potential energies gained when driving uphill, which can then be recovered in push mode when braking or when driving downhill.

The total driving resistance, ie the counteracting dynamic driving force due to the deformation work performed on the wheels and the road and / or air resistance and / or gradient resistance (downhill force), is F _W = F _Roll + F _Air + F _gradient .

The drive power (driving resistance power) to be used on the drive wheels alone to overcome the individual driving resistances is a power loss that does not contribute to dynamic acceleration and is P _W = F _W ∗ v / 3600 with P _W [kW], F _W [N] and v [km / h] (see Bosch, automotive paperback, 28th edition 2014, p. 774 ff .)

Since a potential energy obtained after overcoming the gradient resistance can largely be converted back into electrical energy (recuperable) except for thermal losses by means of generator operation of an electric motor and can be stored in energy stores, the gradient resistance can subsequently be left out of consideration.

wobei µ_r der dimensionslose Rollreibungs-Koeffizient, F_N = m^∗g (m = Masse, g = 9,81 m/s^-2) die als Normalkraft senkrecht zum Boden wirkende Gewichtskraft des Fahrzeuges, Cw der spezifische dimensionslose Luftwiderstandsbeiwert, A die Frontfläche des Fahrzeuges, Rho die Luftdichte und v die Geschwindigkeit des Fahrzeuges bedeuten.An overall driving resistance resulting solely from the static and dynamic friction and to be compensated for by an engine power is thus approximately F _W = F _Roll + F _Air = µ _r ∗ F _N + $\frac{1}{\mathrm{2nd}}{\mathrm{C.}}_{w}A\ast v^{\mathrm{2nd}}\ast \mathrm{Airtight}\mathrm{Rho},$

where µ _{r is} the dimensionless rolling friction coefficient, F _N = m ^∗ g (m = mass, g = 9.81 m / s ^-2 ) is the weight force of the vehicle acting as normal force perpendicular to the ground, Cw is the specific dimensionless drag coefficient, A the Front surface of the vehicle, Rho means the air density and v the speed of the vehicle.

The power loss P _W or a fuel or power consumption that is not used for dynamic propulsion is therefore essentially dependent on the rolling friction force increasing proportionally with the vehicle weight and the air resistance of the vehicle increasing quadratically with the vehicle speed.

The power consumed for this is proportional to the overcoming of these forces, the instantaneous speed and, in the case of an internal combustion engine, also to the fuel consumption per unit of time. $$P_W\left(v\right)=F_W\ast v=\left({\mu }_r\ast F_N+\frac{1}{\mathrm{2nd}}{\mathrm{C.}}_{w}A\ast \mathit{Rho}\ast v^{\mathrm{2nd}}\right)\ast \mathrm{v}={\mathrm{C.}}_1\times \mathrm{v}+{\mathrm{C.}}_{\mathrm{2nd}}\times {\mathrm{v}}^{\mathrm{3rd}}\left[\mathrm{watt}\right]$$

With µ _r = 0.01, F _N = mxg = 575 kg x 9.81 mxs ^-2 , c _W = 0.21, wind pressure end face A = 1.5225 m ² and air density Rho (200m height) = 1.202 kg / m ³ , the constants C ₁ , C _{2 are} calculated as C ₁ = 56.41 [kg xmxs ^-2 ] = 56.41 [N] and C ₂ = 0.19 [kg / m].

Since the fuel consumption of the vehicle is in the plane with and without wind flow for different speeds on a motor vehicle standing in a roller test stand along with a flow channel can be measured and knowing that 1 liter of diesel fuel provides approx. 10 KWh of energy, corresponding value tables and the speed-dependent fuel consumption C (v) corresponding characteristic curves C (v) or power loss characteristics P (v) can be measured or calculated will.

It is also known that the efficiency of an internal combustion engine drops sharply during load changes (positive or negative accelerations; change from train operation to push operation) as well as with oversizing, which in turn has a negative impact on exhaust gas emissions. The more continuously an internal combustion engine works, the more efficiently and with lower emissions it can be dimensioned and operated.

It is therefore the task of combining the advantages of the electric motor as well as the internal combustion engine drive in hybrid vehicles in which the electric motor performs the main drive in such a way that the torques to be transmitted to the road by means of the drive train are as optimal as possible for the operating states constant speed and acceleration , ie generated as energy-saving as possible and in particular fuel-saving and divided between the drive components and the torques arising in the braking and deceleration operating states can be converted back into electrical energy in the best possible way.

The object of the invention is therefore to provide a control method for the drive train of a hybrid motor vehicle, in particular for its internal combustion engine, so that it can be driven without emissions up to 150 km when operated by means of an electric motor and when operated by means of an internal combustion engine in compliance with the EU emissions standard Euro -6 has a maximum fuel consumption of 0.5l / 100km in city traffic and a maximum fuel consumption of 1.5l / 100km in interurban traffic. Furthermore, it should be able to accelerate from 0-100Km / h in 5s and still have a competitive price compared to vehicles currently operated exclusively with internal combustion engines.

According to the invention, these objects are achieved by the characterizing features of main claim 1.

Advantageous embodiments of the invention are characterized in more detail in the respective subclaims.

The method according to the invention is characterized in that the hybrid drive train is controlled exclusively by the electric motor by actuating the accelerator pedal until a transition speed V _Ü = 30 km / h +/- 10 km / h, preferably V _Ü = 30 km / h is reached and that the internal combustion engine is then switched on, wherein during an actuation of the brake pedal and when driving downhill, previously mechanically obtained kinetic energy or potential energy is converted back into electrical energy (recuperated) by generator operation of the electric motor and stored in the electrical energy store and that the internal combustion engine , exclusively depending on the measured instantaneous speed v of the motor vehicle and in particular independently of the position of the accelerator pedal or the brake pedal via a speed-dependent power loss control characteristic curve P (v) or fuel consumption control Line of identification C (v) only provides the energy that is required to compensate for the power loss caused by speed-dependent driving resistance (rolling resistance, air resistance) and electrical consumers.

According to the invention, the energy to be provided via the internal combustion engine can hereby be reduced to less than 50% of the total energy used without the energy store having to be discharged.

Since, due to the quadratic dependence of the air resistance on the respective speed, the largest non-recoverable energy component is only generated at higher speeds and since only a very small non-recoverable power is consumed as power loss at low speeds, up to a transition speed v _ü of approx. 30 can Km / h on the connection of the internal combustion engine to be dispensed with.

According to the invention, this is only after reaching the transition speed to overcome the rolling friction resistance and to overcome the air friction resistance or to compensate for the resulting power losses, the internal combustion engine switched on via a speed-dependent power loss control characteristic P (v) or knowing that 1 liter of diesel fuel has an energy content of approx. 10 kWh, via a correspondingly calculable speed-dependent fuel consumption -Control characteristic C (v) controlled.

Dynamically positive accelerations initiated by actuation of the accelerator pedal thus take place exclusively via the electric motor, the energy store of which it is discharging is thereby discharged. Dynamically negative accelerations (braking processes) initiated by operating the brake pedal or pushing operations when driving downhill are used to charge the energy store via the electric motor operating in generator mode.

In contrast to conventional hybrid vehicles, the driver has no influence on the operating state of the internal combustion engine or the power output by the internal combustion engine when the accelerator pedal is actuated, which is conventionally referred to as an accelerator pedal in mainly internal combustion engine-operated motor vehicles.

The exhaust-gas-free electric motor represents the main drive in the present case and the non-exhaust-gas combustion engine is only switched on to the electric motor to overcome the driving forces (rolling friction resistance, air friction resistance) or to overcome or compensate for the thermal power losses that occur during energy conversions.

A power distribution of approximately 70% is preferably selected for the electric motor and approximately 30% for the internal combustion engine, the internal combustion engine not contributing a force or torque component to the dynamic acceleration of the motor vehicle, but rather being switched on only to overcome or compensate for such power losses, which due to linear or quadratic speed-dependent driving resistance (Rolling friction resistance, air friction resistance) or during energy recuperation as thermal losses or as an additional power requirement when switching on electrical consumers.

If, compared to the electric motor, a very small diesel engine is used, which only contributes about 30% to the total drive power, i.e. 70% are taken over by the electric motor, the costs for exhaust gas cleaning can also advantageously be significantly reduced, in particular if the diesel engine is preferably provided with a turbocharger which increases the efficiency thereof, in addition to exhaust gas recirculation. Since the electric motor preferably supplies approximately 70% of the total power of the drive, a sufficiently large driving power reserve is also available for pure electrical operation.

It is particularly advantageous that different engine output variants can only be realized through the unique design of the electric motor and that nothing has to be changed on the control curve (consumption curve) of the internal combustion engine, because then no further exhaust gas tests have to be carried out for this vehicle type. If a specially designed electric motor with the same control curve for the internal combustion engine can also be used in other vehicle variants, no further exhaust gas tests need to be carried out. This results in considerable potential for reducing development costs and risks. The development time when developing a new vehicle type can also be significantly reduced. This results in a very great economic advantage.

Advantageously, due to the fact that the internal combustion engine is switched on according to the invention, which goes beyond a conventional automatic start / stop function to reduce fuel consumption in standstill phases, the exhaust gas values can be increased by approx. Can be reduced by 50% / km. By controlling the internal combustion engine according to the invention, the energy to be supplied by the internal combustion fuel can be reduced to less than 50% of the total energy to be used without the need for Energy contribution of the internal combustion engine would otherwise have to be used for electrical energy or the accumulator would have to be charged.

Since an optional CVT transmission has a constant input speed at a variable output speed over a wide range, a diesel engine in particular can be operated at optimum efficiency without an additional controller. It is therefore advantageous to also automatically switch off a diesel engine running below an optimal speed.

The power P (v) of the connected internal combustion engine required to overcome the rolling friction resistance and air friction resistance or its fuel consumption C (v) are particularly advantageous via a speed-dependent first power control characteristic of the function P _v (v) = C ₁ xv + C ₂ xv ³ controlled with C ₁ = 56.41 [N] and C ₂ = 0.19 [kg / m].

The fuel consumption values C (v) determined in l / h as a function of the speed are given in a table of values below, taking into account the information from motor vehicle and tire manufacturers and typical c _W values, and in Fig. 3 reproduced as a graph (with m = 575 kg): V [km / h] Fuel [l / h] 0 0.00E + 00 5 2.09E-02 10th 4,26E-02 15 6.60E-02 20th 9.18E-02 25th 1,21E-01 30th 1.54E-01 35 1.92E-01 40 2,36E-01 45 2.86E-01 50 3.44E-01 55 4.10E-01 60 4,85E-01 65 5.69E-01 70 6,65E-01 75 7.71E-01 80 8.90E-01 85 1.02E + 00 90 1.17E + 00 95 1.33E + 00 100 1.51E + 00 105 1.70E + 00 110 1.91E + 00 115 2.14E + 00 120 2.38E + 00 125 2,65E + 00 130 2.93E + 00 135 3.24E + 00 140 3.57E + 00 145 3.92E + 00 150 4.30E + 00

Since, according to the invention, only the power lost due to driving resistance is to be taken over by the internal combustion engine and since part of the energy used for accelerations and uphill driving can be recovered during braking and downhill driving, a currently used power can be represented by the currently required fuel consumption, which eliminates the problem of optimal torque distribution on the electric motor and internal combustion engine can be represented by a function that only shows a fuel consumption value depending on the speed, which is then available to the internal combustion engine. A central engine management control unit thus processes the instantaneous speed read out by speed sensors as an input value and outputs a fuel consumption value according to C (v) as an output value.

The position of the accelerator pedal therefore no longer plays a role in the regulation of the internal combustion engine operated according to the invention. Accelerator pedal and brake pedal positions are forwarded to the electric motor control unit via the central engine management control unit, with functions relating to operational safety how the starting of an ABS or system-critical discharge or overcharge states of the energy store can be taken into account.

The method according to the invention is also advantageous because the recuperation can take place without complicated models and trip memories. Complicated maps, case distinctions and ramifications in the control system that tend to occur nonlinearities would also include the risk that a control system may oscillate. According to the invention, all control components required for torque distribution are separated from one another and are linear. As a result, the overall system working according to the invention is also very stable.

It is particularly advantageous for a motor vehicle driver to be able to use an energy selection device, preferably a potentiometer circuit, to choose whether and how much electromotive or internal combustion engine energy he wants to use when driving, or to be able to determine whether and to what extent the accumulator or another store of electrical energy is to be discharged or charged. This takes place by means of optional control by means of fuel consumption control curves C _n (v) (n = 0,1,2,3, ... max) in the range between a lowest control curve C ₀ (v) = C (v) - 100% x C (v) via, for example, a first control characteristic C ₁ (v) = C (v) - 50% x C (v) below the main control characteristic C (v) up to an uppermost control characteristic $${\mathrm{C.}}_{\mathrm{Max}}\left(\mathrm{v}\right)=\mathrm{C.}\left(\mathrm{v}\right)+\mathrm{20th}\%\times \mathrm{C.}\left(\mathrm{v}\right).$$

By shifting the power loss values or the fuel consumption values used for this purpose, it is possible in principle to use the electric motor to overcome the friction and conversion losses and to discharge them to that extent or to drive them with electricity alone, and to discharge the energy store or one To avoid overloading and thereby either completely avoid or at least reduce the consumption of combustion fuel.

By shifting upwards, it is possible to reverse the use of the electric motor and, to that extent, to prevent the energy store from being discharged, the consumption of Combustion fuel is naturally increased here.

With an advantageously additionally operated turbocharger, it is also possible to further increase the efficiency of a diesel engine by means of exhaust gas recirculation and to reduce the nitrogen oxide values that occur so that they do not have to be further treated. This can alleviate or solve one of the biggest problems with a diesel engine.

Since no inexpensive catalysts for nitrogen oxides have hitherto been available for small diesel engines, the drive control method which works in a hybrid manner according to the invention is particularly advantageously suitable, even in diesel motor vehicles, such as the Smart® from Daimler AG to meet the Euro 6 emissions standard.

As a result of using the method according to the invention in one with a corresponding device as described Fig. 1 equipped motor vehicle, it is possible to drive up to 150 km completely without emissions and with a maximum consumption of 1.5l / 100km to be able to drive without any range restriction. The drive according to the invention and the control method according to the invention make it possible to accelerate a vehicle up to a mass of 500 kg, in particular a three-wheeled motor vehicle (trike) from zero to 100 km / h in 5 seconds, and thereby to reach a maximum speed of 150 km / h to let. Due to the special feature of an automatic start and stop, which only switches on the internal combustion engine, preferably a diesel engine, starting at around 30 km / h and can also switch it off again when the operating conditions are not the same, a motor vehicle working with the method according to the invention becomes even without major exhaust gas cleaning effort Far below the limit values of the European emissions standard Euro-6 and may therefore also meet future, even stricter exhaust gas limit values. A vehicle mass lower than approx. 500 kg allows a correspondingly even smaller drive and an accumulator correspondingly reduced capacity, as a result of which the costs of the motor vehicle can advantageously be kept at the current level of a small car.

The method according to the invention is advantageously used in a full-hybrid motor vehicle connected in series or in parallel, the power of the electric motor exceeding the power of the internal combustion engine and the accumulator capacity being dimensioned sufficiently that the acceleration tasks are carried out exclusively with the electric motor can and converted braking energy released during braking back into electrical energy, ie can be recovered.

It is particularly advantageous to use a trike, i.e. to design a motorized three-wheeled light vehicle, preferably designed as a closed car trike or as an open motorcycle trike, with a front wheel and two rear wheels, in particular also a twike, as a hybrid vehicle working with the method according to the invention and / or equipped with the device according to the invention. In any case, four-wheeled vehicles are also referred to as tricycles in Germany under traffic registration law if one pair of wheels is designed as a twin wheel or the distance between the center of the two tire contact patches is not more than 465 millimeters.

• Fig.1 zeigt ein Ausführungsbeispiel der erfindungsgemäßen Vorrichtung zur Durchführung des erfindungsgemäßen Verfahrens in einer Prinzip-Darstellung.
• Fig.2 zeigt eine geschwindigkeitsabhängige erfindungsgemäße Verlustleistungs-Steuerkennlinie P(v) für den Verbrennungsmotor.
• Fig.3 zeigt eine mit der Verlustleistungs-Steuerkennlinie P(v)nach Figur 2 korrespondierende geschwindigkeitsabhängige Treibstoff-Verbrauchskurve C(v) sowie das Kennlinien-Feld von Steuerkennlinien C_n(v) innerhalb eines vorzugsweise zwischen C₁(v) und C_max(v) wählbaren Einstellbereichs.
• Fig.4 zeigt einen gesetzlich genormten geschwindigkeits-zeitabhängigen Fahrzyklus v(s), beispielhaft für Motorräder und Trikes Fig.1 zeigt in einer Prinzip-Darstellung einen seriell geschalteten Hybridantrieb für ein Kraftfahrzeug mit einem Elektromotor 6 und einem Verbrennungsmotor 8 sowie mit zwei Antriebsrädern 1, welche mittels Antriebswellen 4 über ein zwischengeschaltetes Ausgleichs-Differentialgetriebe 3 mechanisch mit einem Getriebe 5 verbunden sind, wobei am Antriebsstrang anliegende Drehmomente über die Antriebsräder 1 auf die Fahrbahn übertragen werden bzw. im Schiebebetrieb an den Antriebsrädern 1 erzeugte Drehmomente über das Getriebe 5 auf den im Generatorbetrieb laufenden Elektromotor 6 zurückübertragen werden. Das Getriebe 5 ist vorzugsweise ein keinen Rückwärtsgang aufweisendes stufenlos arbeitendes CVT(Continuously Variable Transmission)- Getriebe. Das Getriebe 5 ist über eine der Antriebswellen 4 starr mit dem den Hauptantrieb darstellenden Elektromotor 6 gekoppelt, welcher seinerseits über eine Kupplung 7, welche eine elektrische oder auch eine Fliehkraftkupplung sein kann, mit einem über einen Anlasser 9 startbaren Verbrennungsmotor 8 verbunden ist. Der Verbrennungsmotor 8 ist über ein Verbrennungsmotor-Steuergerät 10 nicht nur mit dem zentralen Motormanagement-Steuergerät 12, sondern auch mit zusätzlichen (nicht dargestellten)Baugruppen, wie z.B. Abgasrückführungs-EGR-Ventilen, Lambdasonden, Turboladern, Diesel-Partikel-Filtern(DPF) und Katalysatoren verbunden und bildet eine selbständig funktionierende Einheit.

In the drawings, the method according to the invention and the device suitable for carrying out the method in a hybrid vehicle are described and explained in more detail using an exemplary embodiment.

• Fig. 1 shows an embodiment of the device according to the invention for performing the method according to the invention in a schematic diagram.
• Fig. 2 shows a speed-dependent power loss control characteristic P according to the invention for the internal combustion engine.
• Fig. 3 shows a with the power loss control characteristic P (v) Figure 2 Corresponding speed-dependent fuel consumption curve C (v) and the characteristic curve field of control characteristic curves C _n (v) within a preferably adjustable setting range between C ₁ (v) and C _max (v).
• Fig. 4 shows a legally standardized speed-time-dependent driving cycle v (s), exemplary for motorcycles and trikes Fig. 1 shows a schematic representation of a series-connected hybrid drive for a motor vehicle with an electric motor 6 and an internal combustion engine 8 and with two drive wheels 1, which are mechanically connected to a transmission 5 by means of drive shafts 4 via an intermediate differential gear 3, with the drive train being applied Torques are transmitted to the roadway via the drive wheels 1, or torques generated on the drive wheels 1 during pushing operation are transmitted back via the transmission 5 to the electric motor 6 running in generator mode. The transmission 5 is preferably a continuously operating CVT (Continuously Variable Transmission) transmission which has no reverse gear. The transmission 5 is rigidly coupled via one of the drive shafts 4 to the electric motor 6 which represents the main drive, which in turn is connected via a clutch 7, which may be an electric or also a centrifugal clutch, to an internal combustion engine 8 which can be started via a starter 9. The internal combustion engine 8 is connected via an internal combustion engine control unit 10 not only to the central engine management control unit 12, but also to additional assemblies (not shown), such as exhaust gas recirculation EGR valves, lambda sensors, turbochargers, diesel particle filters (DPF). and catalysts connected and forms an independently functioning unit.

The electric motor 6 is an electric motor control unit 13 and the internal combustion engine 8 is the internal combustion engine control unit 10 designed as a CPU. The central higher-level engine management main control unit 12 is provided not only to be supplied with a signal corresponding to the driver's wish in terms of quality and quantity of the energy choice by an energy selection device 11 assigned to it, but also to be supplied by two in the area of the drive wheels 1 arranged speed sensors 2 and on the brake pedal 15 and on the accelerator pedal 16 each position sensors of the respective instantaneous speed v of the motor vehicle and the respective position of the brake pedal 15 and the accelerator pedal 16 to receive corresponding electrical signals. In addition, 12 values are entered into the main engine management control unit Read fuel consumption sensor, which indicates, depending on the speed, which amount of fuel consumption is due to the internal combustion engine 8. These signals are processed in accordance with the control method according to the invention, ie both the voltages and currents required for the torque output of the electric motor 6 and for the torque absorption of the electric motor 6 running in generator mode are generated, and the electric motor 6 is correspondingly acted upon electrically. In addition, the internal combustion engine control unit 10 controlling the internal combustion engine 8 switches the internal combustion engine 8 on from a selectable transition speed, preferably 30 km / h, whereby after measuring the fuel consumption amount required according to the invention by means of a fuel amount sensor, this fill amount is transferred to the internal combustion engine 8 or in the case of a diesel engine is supplied by means of an actuator for diesel injection. Optionally, an internal combustion engine 8 that is once connected to the drive train of the electric motor 6 via the motor management main control unit 12 by means of an electrical clutch 7 can also be switched off again if necessary. Up to a speed of approx. 100 km / h, the automatic transmission 5 ensures that the internal combustion engine 8 always runs in the range of the most efficient speed.
The electric motor 6 must at least be able to provide the power or be able to take it up in generator mode, which is required in order to generate a desired acceleration and to be able to recover a desired deceleration power or the mechanical energy released in this way into electrical energy.

Ultimately, it is not critical to specify a specific power ratio between the electric motor and the internal combustion engine, but rather to design the power of the electric motor so large that it provides at least the necessary torque to be able to overcome the statutory minimum gradients or those required by the designer To be able to achieve accelerations. The internal combustion engine should have at least enough power to compensate for the power losses that occur while driving.
With regard to the total power P available for driving the motor vehicle, the engine power P is _VM small compared to the electric motor power P _EM , preferably with P _VM = 30% and P _EM = 70%.

The capacity of an electrical energy storage device 14 which is electrically connected to the electric motor 6 via the electric motor control unit 13 is to be designed or selected such that it is possible to operate purely electrically, i.e. up to a speed of 30 km / h. to drive exclusively in electric motor operation and to be able to absorb and deliver all possible recuperable energy. An accumulator is conventionally selected as the electrical energy store. However, a supercapacitor can also be selected in the present case. The latter have only about 10% of the energy density of an accumulator, but on the other hand 10 to 100 times the power density of an accumulator. This makes supercapacitors particularly suitable as a replacement or supplement to conventional accumulators if, as in the present case, rapidly changing charging and discharging cycles are required for the purpose of, in particular, braking energy recovery (recuperation).

The output of the internal combustion engine 8 is to be dimensioned at least sufficiently large that the desired maximum speed of the vehicle, in the present case 150 km / h, can be achieved and also maintained in the additional internal combustion engine operation.

On the drive wheels 1, the sensors, which also act in an ABS (automatic braking system), are preferably arranged as speed sensors 2, which in turn are electrically connected to the higher-level engine management control unit 12.

Fig. 2 shows a graph P (v) = C ₁ xv + C ₂ xv ^{3 of} the speed-dependent control characteristic curve P (v) according to the invention for the internal combustion engine with C ₁ = 56.41 [kg ^∗ m ^∗ s ^-2 ] = 56.41 [N] and C ₂ = 0.19 [kg / m].

The respective instantaneous speed v is plotted on the abscissa and the power loss P (v) [kW] that occurs due to driving resistance is plotted on the ordinate. Since the internal combustion engine according to the invention only from a transition speed v _ü = 30 km / h is switched on, only the ascending function values from here are decisive for the control of the internal combustion engine 8.

The internal combustion engine control unit 10 receives a start signal for starting the internal combustion engine 8 and a request for the consumption power from the engine management control unit 12. The electric motor control unit 13 receives the necessary control signals from the engine management control unit 12 and is thereby triggered either in the electromotive operating state by means of the Generate accumulator 14 connected electric motor 6 torques or use torques generated in generator operation of electric motor 6 to recharge the accumulator (14), that is to say to recuperate energy. The speed of the motor vehicle can thus either be increased, maintained or reduced. With a control signal passed on to the engine management control unit 12 via an energy selection device 11, the motor vehicle driver can decide at any time whether and which fuel consumption, measured in l / h or cm ³ / h, should be used optionally.

Fig. 3 shows the characteristic curve field of fuel consumption control characteristic curves C (v) within a preferably adjustable setting range between C ₁ (v) and C _max (v).

The internal combustion engine 8 is preferably controlled by one of these consumption curves. This specifies the fuel consumption requested or permitted as a function of the speed, as a result of which the applicable exhaust gas standards can be met.

The fuel consumption control characteristic curves C (v) correspond to a preferred shift of the function values of the in FIG Fig. 2 drawn main control characteristic curve P (v) in the plus-ordinate direction, which corresponds to an additional fuel consumption or in the minus-ordinate direction, which corresponds to an under-fuel consumption. This is preferably done within the limits of + 20% in the plus ordinate direction upwards and -50% in the minus ordinate direction downwards. In the zero position of the energy selection device 11 designed as a setting button, a purely electromotive device can also be used Driving operation without fuel consumption can be requested, which corresponds to a - 100% shift in the minus ordinate direction downwards.

Fig. 4 shows an example of a legally standardized driving cycle for measuring fuel consumption and exhaust emissions for light motor vehicles, such as motorcycles and trikes for city traffic according to the worldwide harmonized test cycle "Worldwide harmonized Motorcycle Test Cycle" (WMTC) phase 2 part 1. Together with the from the fuel consumption curve Fig. 3 Using the data to be extracted, the consumption for the relevant driving cycle and the distance traveled can be determined using numerical integration. For a motor vehicle with a mass of 550 kg, the quotient consumption / distance traveled, for example, results in a fuel consumption of 0.55 liters / 100 km.

By means of the control method according to the invention, the electromotive travel drive mediated via the electric motor 6 together with the electric motor control device 13 and the internal combustion engine travel drive mediated via the internal combustion engine 8 together with the engine control device 10 can also be carried out completely independently of one another on the same drive train with the drive shafts 4, as long as that The engine management control unit 12, which acts in a centrally superordinate manner, does not connect the two motor components of the hybrid drive in a program-related manner, and the internal combustion engine control unit 10 and the electric motor control unit 13 do not take on further torque-dependent or other inseparable tasks on the drive shafts 4, and both motors 6, 8 together with the accumulator 14 are sufficiently large enough to be able to provide the legally required mileage required in driving operations (see Delegated Regulation (EU) No. 134/2014 from 16.12.2013 in connection with VO (EU) Nr.168 / 2013 from 15.01.2013 with regard to requirements regarding the environmental compatibility and performance of the drive unit of light motor vehicles, such as VTS-741.41 chapter 3 article 54 paragraph 3 - slope / minimum torque).

Reference symbol list:

1

Drive wheels

2nd

Speed sensors

3rd

Differential differential

4th

Drive shafts

5

transmission

6

Electric motor

7

clutch

8th

Internal combustion engine

9

Starter

10th

Internal combustion engine control unit

11

Energy selector

12th

Engine management control unit

13

Electric motor control unit

14

Electrical energy storage (accumulator)

15

Brake pedal

16

Accelerator pedal (accelerator pedal)

Claims (5)

1. Method of controlling the drive train of a hybrid motor vehicle with at least one electric motor (6) and at least one combustion engine (8), at least one speed sensor (2) and at least one electrical energy storage system (14) as well as a brake pedal (15) and an accelerator pedal (16), characterised by the fact that the hybrid drive train is controlled exclusively by the electric motor (6), by means of operation of the accelerator pedal (16), until a transition speed of V_τ = 30 km/h +/- 10 km/h, preferably V_U = 30 km/h, is reached and the combustion engine (8) is then activated, whereby kinetic energy previously generated mechanically in operation of the brake pedal (15) and when travelling downhill or potential energy from generator operation of the electric motor (6) is converted back into electrical energy (recuperated) and stored in the electrical energy storage system (14), and that the combustion engine (8) provides only the energy required to compensate for the power loss owing to speed-dependent driving resistances (roll resistance, air resistance) as well as electrical consumers, depending exclusively on the measured present speed v of the vehicle and specifically independently of the position of the accelerator pedal (16) or the brake pedal (15) over a power loss control characteristic curve P(v) or a fuel consumption characteristic curve C(v) by which it is controlled depending on speed.
2. Method of controlling the drive train of a hybrid motor vehicle according to claim 1, characterised by the fact that the electric motor power P_EM = 70 % and the combustion engine power P_VM = 30 % of the total drive power that should be available.
3. Method of controlling the drive train of a hybrid motor vehicle according to claim 1 or 2, characterised by the fact that the power P(v) from the activated combustion engine (8), which is required to overcome the rolling friction resistance and air friction resistance by compensation or the fuel consumption of the same C(v), is controlled via a speed-dependent power loss control characteristic curve P(v) of the function P(v) [watts] = C₁ x v + C₂ x v³ [watts], where C₁ = 56.41[N] and C₂ = 0.19[kg/m].
4. Method of controlling the drive train of a hybrid motor vehicle according to one of the preceding claims, characterised by the fact that further power loss control characteristic curves P_n(v) or fuel consumption characteristic curves C_n(v) where n = 1, 2, 3... in proportion to the first power loss control characteristic curve P(v) can be configured for direct control of whether and to what extent the combustion engine (8) should be activated and for indirect control of a desired electrical energy storage system (14) charging process or discharging process that is dependent on this, by means of a selection device (11), preferably a potentiometer and preferably across a range essentially from P₁(v) = P(v) - 50 % x P(v) below to P_max(v) = P(v) + 20 % x P(v) above the same or from C₁ (v) = C(v) - 50 % x C(v) below to C_max(v) = C(v) + 20 % x C(v) above the same.
5. Method of controlling the drive train of a hybrid motor vehicle according to one of the preceding claims, characterised by the fact that the combustion engine (8) is a diesel engine powered by diesel fuel, preferably with a turbocharger as well as exhaust gas recirculation.

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